Mercedes-Benz C-class Cabriolet review: pricier than an Audi A5 - but is it better?

There comes a time in the affairs of men when a fridge-white Mercedes-Benz convertible with a sail-cloth red hood might seem like a good idea. I'd advise lying down in a quiet room until that feeling passes.

Not that the new C-class cabrio is in any way a bad thing, especially in the 2.1-litre diesel version delivered to a parking spot directly outside my house. It's just that colour combo, with AMG trim badging and bad-boy wheel options, drew stares of the type normally reserved for rambunctious bankers, or arriviste lottery winners. I drew back from the window not wanting to be associated with this ostentatious display of 'we're-not-all-in-it-together' and slunk away at dawn's first break.

Which is a shame, since the C-class, the first rung in what its maker deems “proper Mercedes ownership”, is a darn nice thing. It's the first drophead Mercedes C-class since the previous CLK offered four-seat wind-in-the-hair motoring - that car was also based on a C-class platform. And, like the old first-generation W124 E-class cabriolets, the C cab offers a generous and sociable way to travel. Four-up, with the roof down, you can coast under the cirrocumulus and soleil brille, observing birds on the wing and conversing about the affairs of the day with your rear-seat passengers. What could be finer?

Fridge white with a sail-cloth red hood, this particular example of the C-class Cabriolet makes a statement wherever it's parked

Actually the C-class takes conversation to new levels, with an electronically deployed Air Cap wind deflector which rises up, like a James Bond villain's doomsday weapon, from between the seats. It calms conditions and flailing hair in the rear seats. Shame then, that although those seats are comfortable, head room with the hood up is in short supply and leg room isn't exactly copious, either. Some give and take between front and rear-seat passengers is required. Nor is there much room for your passengers' luggage, with the quoted figure of 285 litres less than that of a family hatchback, which is reduced still further with the hood furled.

Some give and take between front and rear-seat passengers is required

That process takes place in seconds with the press of a button at up to about 30mph; the sort of swanky street theatre you'll never tire of, though your neighbours might. The rest of the cabin is well finished and attractive, if a bit flash in places. The AMG-Line trim standard is pretty stacked, from the seat-belt presenters to the electronic control of everything you might conceivably desire.

Leather-upholstered seats are heated and air-conditioned and an optional £3,000 Premier Pack includes Comand on-line with an 8.4in colour screen, 3D map display, WiFi hot spot and driven services. The pack also includes the slightly brittle-sounding Burmester Surround sound system and front seat memories.

The C-class Cabriolet is slightly cramped, and some of the expensive driver assistance tech should be supplied as standard

For an additional £1,700, the Driving Assistance Package adds some features which should really be standard, such as blind-spot and cross-traffic assistance, and pedestrian assistance. Our test car also had £545's worth of automatic LED headlamps, which work reasonably well most of the time, but seem reluctant to dip for oncoming traffic, unnecessarily dipping for reflective signs and occasional street lamps and, on undulating A-roads, failing to dip for oncoming lorries until the system can “see” their headlamps.

For an additional £1,700, the Driving Assistance Package adds some features which should really be standard

You can have virtually anything you like under the bonnet, from the base model 181bhp, 2.0-litre petrol to the mighty 503bhp, 4.0-litre, twin-turbo V8 in the £78,295 C63 version. In most cases, folk will chose something a bit less fuel-slurping, such as Mercedes's current generation 168bhp/295lb ft twin-turbo 2.1-litre diesel driving the rear wheels via Merc's own nine-speed automatic. With a top speed of 145mph and 0-62mph in 7.5sec, it's brisk enough and the Combined fuel consumption of 68.9mpg eases the running costs a little, proven by our average of 52.7mpg on a long and speedy run.

Not so good is the growling, rattling nature of this engine when extended; they're all like that, although the nine-speed auto does a great job of hiding it by keeping the rev-counter needle in the middle of the dial. Steering-wheel paddles also allow you to simply change up and reduce the racket, but this is something less of a driver's driveline and you might be better-off looking at Mercedes's more powerful and mellifluous V6 diesels instead.

The Mercedes C-class is a "boulevardier with the best of them" – but don't overdrive it

Riding on 18in wheels with the lowered sports suspension option, the cabriolet is firm, borderline harsh. There's 125kg of strengthening in the car over the equivalent coupé and you can feel that extra weight as the suspension struggles to maintain its equanimity. Body shake is at a minimum, but still evident as a kind of discreet shimmy around the front of the car. On a smooth road, the cabrio is a boulevardier with the best of them, but you don't want to overdrive it.

The handling is precise, the nose points faithfully and body roll is well controlled, but the optional lane-keeping system, together with the sports direct steering option and sports suspension, has the effect of making it feel sharp and slightly inconsistent. Stick the suspension in Comfort mode and, given the limitations of the driveline, this is as a good a sports cabrio as you'd want.

Choose your engine wisely, as there are some relative duds in this model's line-up

While the C-class range starts at £27,665, the cheapest version of this handsome Cabriolet is £36,200. There follows the most bamboozling range of options and trim levels you'll encounter outside of a Savile Row tailor, which lands us on the shore of the test car which, optioned up, is just £1,500 short of 50 grand. Ouch.

My abiding memory of this car will be heading off into the dusk from the West Country with the hood down and the Olympics on the stereo. With 300 miles ahead, the anticipation of that long A-road journey proved as memorable and pleasant as the reality. With few competitors, this drophead Merc really is a guilty pleasure, albeit a pricey one. And the bonus of driving this particular example, of course, is that you don't have to look at the colour.

Verdict: Charming four-seat drophead, with room enough (just) for four adults. Well engineered and good looking, but the smallest diesel doesn't suit the car well - a V6 diesel would be better. A guilty and expensive pleasure

Telegraph rating: Four out of five stars

Book a free test drive from your home or office

For all the latest news, advice and reviews from Telegraph Cars, sign up to our weekly newsletter by entering your email here